Spark plug



Jan. 26? 1943. GQc-z.V BURRELL ETAL 2,309,235

SPARK PLUG Filed sept. 15, 1941l E EEUREELI LEU EUHRELL f. my

fill/ H Patented Jan. 26, 1943 SPARK PLUG George G. Burrell, Blairstown, and Leo Burrell,

. Bes Moines, Iowa.

Application September 15, i941, Serial No. 410,868

4 Claims.

The principal object of this invention is to provide a spark plug that against mois ture, condensate and the l'lr A further object a spark plug which ay he huilt into the block of a motor, that will init ti e changing of the points of the plug, and one that is sealed against moisture when in place.

A still further object of this invention is to provide a high tension shield :for spark plugs, distributors, or the like that is water-proof, that statically shields the inte, and that provid ed with a mesi tor nition system f ventina. is to provide this invention is to extremely are attained hereinafter more fully set forth, pointed out in our claims, and illustrated in the accompanying drawing, in which:

Fig. 1 is a side cross sectional view ci our plug ready for use.

Fig. 2 is a side elevational View oi the spark plug more `fully illustrating its structure.

Fig. 3 is a side elevational view ci the removable point carrier and insulating sleeve shown in Fig. 1.

Fig. 4 is a bottom elevational view of the plug.

Fig. 5 is an enlarged cross sectional view of the upper portion of the plug shield showing the insulating cap and stylus contact point.

Fig. 6 is an enlarged sectional view oi. a portion of a motor block illustrating the method of placing the points in a motor head Without the use of a base on the plug.

Spark plugs have followed the same 2gern-eral-y line for many years. They have exposed porces lain insulators, are not statically shielded, are. not water-proof, and do not permit the changing' of the points. Furthermore, they are subject to breakage and have exposed contact wires and connections. These plugs are very fragile and due to changes of operating temperature, the porcelalns crack and become short-circuited. We have overcome such disadvantages as will be appreciated and as will be hereinafter more fully set forth. i

Referring to the drawing, We have used the numeral i0 to indicate a base portion of the usual type and having the threaded sleeve memher Il thereon so that it :may be screwed into 'a .motor block or head. The inside base chamber ci the base Il) is tapered and the upper inside portion is threaded t/o receive an elongated sleeve member or shield it. This shield portion can be threaded into the base member i0 and has. its inside hollow. I have used the numeral i3 to inclicate a porcelain insulator having therein a central electrode l il and an enlarged tapered portion I5 as shown lig. l. The upper portion of the insulator extends upwardly to form a sleeve IB, leaving ,a shoulder il between this upright portion l5 and the enlarged portion i5. The numeral il indicates a hr' crimped and secured about the enlarged tapered portion it and having 'thereon an electrode which extends downwardly and thence is curved around the center electrode ill adjacent the hase of the plug Il! as shown in Fig. a. lt will be noted, by referring to Fig. a, that the curled portion of the ground elecftrode I9 extends in a circle having a constantly decreasing gap between the central electrode I4 and the ground electrode IS. This provides a self-adjusting point giving the plug a much longer life and much more sparking surface. The insulator I3 is placed within the base member I0 and the sleeve I2 ls then threaded into the top of the base l0, forcing the band I8 into contact with the base member IU in the manner shown in Fig. l. The shoulder I1 is filled with a seal\ ing compoundA and the tightening action of the sleeve I2 enforcing the tapered sleeve I8 into the tapered receptacle of the base I0 provides sumcient seal to prevent compression, leaks, and to make a positive ground for the electrode I9. The numeral 20 indicates a stylus on the upper end of the insulator sleeve I6 which is in electrical communication with the electrode I4 as shown in the drawing. We have used the numeral 2| to designate an insulative cap having the tapered inside chamber 22 and capable of being threaded into the upper end of the sleeve I2. The nu meral 23 indicates an ordinary high tension wire over which the sleeve 2| is placed, and which has its end portion forced onto the stylus 20 to establish contact with the center wire after which the cap 2| is threaded into place, thereby forcing the wire down on and into contact with the stylus 20, at the same time providing an inherent seal between the cap portion 2l and the Wire 23. If the wire 23 is of the shielded type, the shield 24 is connected by spring clips or the like 25 to a rim or bead 2B formed about the upper end of the Sleeve I2. When the plug as shown in Fig. 1

is placed in a motor block, the whole exterior unit of the plug is shielded from moisture, dirt, oil, air and the like, and is also statically shielded to prevent radio interference. Referring to Fig. 6 of the drawing it will be noted that the base as represented by the base I0, can be formed in the head of the motor. A head so formed has been illustrated in Fig. 6 and designated by the numeral 21. The points are then dropped into the opening so that the sleeve I8 is in contact with the side walls of the head and the sleeve or shield I2 is then screwed into the block. This permits the water jacket to be brought adjacent the plug or motor points for keeping the plug cool and leliminates the forming of a large depression in an ordinary motor head for the accommodation of the spark plug. This structure increases the cooling surface within the heads and provides a cooler plug, as Well as simplifying the structure of the motor block head.

The practical operation of our device is as follows:

plug opening of a motor. The electrode carrier comprising the insulator I3 with its attendant sleeve I8 and enlarged portion I5, sleeves I8, electrodes Il and I9, a'nd stylus 20 is then dropped into the base portion. The cover member or shield I2 is then screwed into the upper end of the base I and forced tightly down upon ythe shoulders I1, forcing the cone formed by the sleeve I8 into the cone formed within the base I0 an-d providing a tight fit. The cap 2| is then placed over the end of the ignition wire, and the end of the wire forced down onto the stylus 20. The cap 2l is then threaded -into the upper end of the shield I2 and by virtue of the tapered inside bore 22, forces the wire tightly against the stylus 20, and at the same time effectively seals the upper end, in conjunction with the wire 23, to form a water-proof unit. The shield 24 of the wire 23 is then clipped by means of the ngers 25 to the bead 26, and the device is ready for use.

This whole unit above the motor head may be immersed in water and will still function properly. There are no exposed terminals or connections, and the porcelain is not subjected to the cooling drafts to permit it to crack from expansion and contraction. The same set of points may be dropped into the motor block 21, and the threaded cap or cover I2 placedA therein in the manner shown in Fig. 6, permitting the water cooling of the head directly adjacent the spark plug. Referring to Fig. 5, this connection may be used on distributor caps and other high tension devices for providing a water-proof shielded contact point, leaving no exposed terminals and preventing the condensation of moisture about the insulated portion of the device to which it is attached.

All of the electrodes are carried on one member, that is, the member shown in Fig. 3, and therefore, the construction shown in Fig. 6 is possible. By using the vcurved electrode I9, greater firing surface is obtained, permitting it to progressively burn oil.r and still retain a gap within the tolerance required by the electrodes or contact points I4 and I 9. With our device, it is possible to have the upper member exposed to the direct blow or draft of the fan for cooling the plug without danger of cracking the porcelain insulator. There is no danger of accidentally touching an exposed contact point or breaking the plug by an inadvertent slip of a wrench or like. The whole plug is shielded electrically and The base member I 0 is threaded into the sparki atmospherically, permitting the use of a cold type plug in all types of motors and the easy replacement of the point portions of the plug without it being necessary to purchase a new base portion or cover member and is of prime importance. The upper portion can be used for a water-proof ignition system by using the structure shown 'in Fig. 5 in conjunction with magnetos, distributors and the like. Our device fuifllls all of our objects and presents many more obvious advantages. The porcelain portion of the device will hereinafter be called an insulator, and the shield I2 will be called a shield member of cover.

Some changes may be made in the construction and arrangement of our improved spark plug without departing from the real spirit and purpose of our invention, and it is our intention to cover by our claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

l We claim:

1. In a device of the class described, a base member, an insulator, a metallic sleeve on said insulator capable of contacting said base member, an electrode on said sleeve, a second electrode extending through said insulator and resting adjacent said 'rst mentioned electrode, a shoulder on said insulator, a shield member capable of being threaded into the top of said base member and holding said insulator and said sleeve in position, a stylus contact point on the upper end of said insulator in communication with said second mentioned electrode, an insulated wire capable of being adjusted on said stylus and in electrical communication therewith, a cap member threaded into the upper end of said shield member and forcing said wire on said stylus and sealing the upper end oi' said shield to provide a moistureproof cap, shielding on said Wire, and a clip member in communication with said shielding capable of establishing electrical contact with said shield portion.

2. In a spark plug, a base portion, an insulating sleeve in said base portion, a shoulder on said sleeve, two electrodes on said sleeve, a shield portion capable of being threaded into said base portion and against said shoulderof said sleeve; said shield extending around and beyond said sleeve portion, and an insulating cap member threaded into the upper end of said shield and capable of holding a Wire; said insulating cap, said wire, said shield and said base forming a water-tight enclosure for said insulating sleeve. 3. In a device of the class described, a hollow base portion, an insulated portion having an electrode extending therethrough longitudinally, a

-second electrode secured to the outside of said insulated member and capable oi' contacting the inside portion of said base member when placed therein, a cover. member threaded into said base member and holding and enclosing said insulated member and said electrodes therein, a contact point on the upper end of said first mentioned electrode capable of being forced into electrical communication with an electric lead wire, and a cap por ion having its inside walls ta having its outside portion threaded sesedtoaxb: received by said cover member for holding said wie and sealing said cover member.

. n a device of the class described,

member, an insulator, a metallic sleeve oi 22;?

insulator capable of Contactin l g said base member, an electrode on said sleeve, a second/electrode extending through said insulator and resting edjacent said rst mentioned electrode. a shoulder on said insulator, a shield member capable of being threaded into the top-of said base member and holding said insulator and` said sleeve in position. sn inside-ted wire capable ci being adjusted on said second mentioned electrode and in electrical communication therewith, and a can member threaded into the upper end of said shield member for sealing the upper end of said shield to provide a moisture-prooi.' cap.

GEORGE G. BURREIL. LEO BURRELL. 

